(1) Field of the Invention
The present invention relates to a recording apparatus for recording picture data and date/time information onto a recording medium such as an optical disc, a playback apparatus, and a recording medium.
(2) Description of the Related Art
Recording picture data onto a recording medium together with the date/time information is meaningful. The date/time information helps the user recall details of the pictures more clearly.
The date/time information is based on a time measured by a timer in the recording apparatus that captures images and records them as picture data. The time measured by the timer is based on a standard time for the region where the recording apparatus is used. Such geographic regions on earth to which standard times are assigned are called “time zones”. A timer in a recording apparatus measures the current time based on the standard time of the time zone in which the recording apparatus is used.
When picture data is recorded onto a recording medium in a time zone, the date/time information in the recording medium is based on the same standard time. However, when picture data captured in two or more different time zones is to be recorded onto a recording medium, it is necessary to select a standard time on which the date/time information should be based.
Suppose a user moves from Japan to Country A taking a video-camera type recording apparatus, and that the time differential between Japan and the Country A is 12 hours. Here, if the user takes pictures during daytime hours in the Country A with the timer being set to the Japanese standard time, the date/time information recorded on the recording medium indicates the nighttime hours due to the time differential. When this happens, the date/time information looses its meaning.
The above problem can be solved if the user sets the timer of the recording apparatus to be based on the standard time of the Country A. Actually, the user can set the timer every time he/she arrives in a different time zone. In this case, however, a problem arises concerning the chronological order of a plurality of pieces of picture data that are based on different standard times. For example, suppose further that the user took a picture in Japan immediately before he/she went to the Country A and recorded the picture data onto the recording medium, then it may happen that the date/time information for the picture appears to be later than that for the picture taken in the Country A. This is because the time differential of 12 hours is not taken into account. If these pieces of picture data are sorted in chronological order, they will be arranged in an improper order. This also makes the date/time information meaningless.